Báo cáo khoa học nông nghiệp " REPORT ON BASELINE SURVEYS IN CANTHO AND AN GIANG PROVINCES " pdf

Baseline study had been carried out during October-November 2007 at Cantho city and during January-February 2008 at An Giang province to assess environment pollution from disposal of was

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Ministry of Agriculture & Rural Development

Project Progress Report CARD Project 023/06/VIE

MS3: REPORT ON BASELINE SURVEYS IN CANTHO

AND AN GIANG PROVINCES

24th April , 2009

Baseline study had been carried out during October-November 2007 at Cantho city and during January-February 2008 at An Giang province to assess environment pollution from disposal of waste of catfish aquaculture ponds and implications for sustainable agriculture production Two districts of Cantho city (O’Mon and Thot Not) and two districts of An Giang (Chau Phu and Phu Tan) were selected based on high numbers of fishpond present in these districts Primary information relating to techniques, socio-economics and environment were recorded by interviews with farmer individually, and was supplemented by observations to evaluate or confirm data This was followed by contact with local officers to collect secondary data as needed Two groups of farmers were chosen (rice growing and fish raising groups) in equal numbers at each site A total

of 240 questionnaires were collected for data analysis

I Socio-economics aspects

Farmers practicing fishpond culture in Cantho are a little younger than those who carried out rice cultivation (43 compared to 49 yrs.); however, there were no difference in ages between these two groups in An Giang province (Table 1) In An Giang province, fish raising farmers were also rice growing farmers, who turned to the fish farming system in order to increase their income By contrast, fish raising farmers in Can Tho are mainly migrants, who hired or bought land from local farmers which explains why the fish raising farmers are younger and with higher formal education level than rice growing farmers

Rice culture has long been practiced in the Cuu Long delta Most of rice growing farmers have more than 20 years experience in rice farming Meanwhile the freshwater fish industry has recently expanded The data on number of years’ experience in fish culture clearly showed that this industry was developed during less than 10 years

The family size was not very much varied between two types of farming system It is about 5 persons/family including a labour force of 3-4 Land tenure areas for rice farming

in both Can Tho and An Giang are much higher than areas used for fish culture The reason might be due to total cost for raising fish is much higher than rice farming (Table 1)

Most of farmers in Cantho and An Giang had concrete or brick houses (80-90%) Thatch house cover less than 10% of rice farming but it is about 15-20% in the case of fish culture Some fish raising farmers are migrants who stay on site temporarily to look after their fish They also have permanent houses at other places

The Cuu Long delta has abundant of water that is why rice or fish culture mainly rely on canals or rivers as their water source Survey data revealed that water pollution is

a concern for 15-25% farmers The evaluation of water quality between upper stream and down stream has also been clearly shown by fish raising farmer in An Giang and Cantho The grade of good and medium was in reverse order between An Giang and Cantho The reason might be water of upper stream from Cambodia is still clean because fish culture

is mainly practiced in Cuu Long delta Waste water was discharge directly to water source by about 70% in An Giang and 80% in Cantho Fish raising farmers having settling ponds are quite few (5-8%) and about 15-25% used waste water for rice cultivation

Table 1 General socio-economics aspects of rice and fish farming households

Items

Fish culture Rice culture Fish culture Rice culture

House types (%)

- Concrete

- Brick

- Thatch

43

42

15

23

73

4

42

39

19

48

44

8 Irrigation water source Canal

and/or river

Canal and/or river

Canal and/or river

Canal and/or river Water quality (%)

- Good

- Medium

- Bad

30

52

18

55

22

23

51

25

24

46

39

15 Wastewater discharge

- River or canal

- Paddy

- Settling pond

80

15

5

24

8

100

Variation on water quality was a concern for farmers (Table 2) Water quality is

good during flooding time (Aug to Dec) mainly because of large flows of water which

dilute and wash away pollutants Waste from fishpond was the major source causing

pollution of rural areas both at An Giang and Can Tho More than 50 % of people in An

Giang used river water for living purposes but more or less this proportion of people in

Cantho utilized tubewell water This figure also represented the severity of water

pollution in river and forcing people to use tubewell water Threats for fish culture might

also come from pesticides discharge from paddy The severity was more in down stream

where pesticides were accumulated

Rainy season and just after flooding time also had good water for irrigation but it

was only accepted by 30 % of total farmers being interviewed

II Economic efficiencies in rice and fish culture

Survey data demonstrated that fish farming generated much higher benefit than

rice about 410 millions dong/ha for fish in comparison with 9 millions/ha for rice

However; total cost for raising 1 hectare of fish was 1,894.6 million dong compared to

only 12.1 millions dong for rice (Table 3)

There was not much difference between Cantho and An Giang province regarding

economic efficiency in agriculture production for rice and fish farming Most of farmers

raising fish had to get loans either from banks or neighbours but percentages of rice

farmers borrowing money were below 50% because total investment for rice production

is much less than for fish culture (Table 4)

Table 2: Quality of water for irrigation and for living & drinking in rural areas

Water source for living & drinking

Water quality for living purpose

Reason for bad quality of water

Time having good water quality for

irrigation

Table 3: Comparison of economic efficiencies in rice and fish farming in Cantho

Mil dong)

Rice farming (X Mil dong)

T value

Table 4: Credit sources for agricultural production

Sources of credit

Interest rate/year (%)

Percentages of farmers in An Giang province accessing credit from banks were higher than that in Cantho (Table 4) This might be because infrastructure of An Giang was better than in Cantho or roads networks in An Giang favoured transportation However, late payment agreement between farmers and companies or traders were more common in Cantho than in An Giang The reason might be due to trading and factories in Cantho had long been developed in Cantho Generally, interest rate/month was about 1% for bank, approximately 2% for agreement of late payment and up to 4% for individual or private sources

III Farmer practices in rice and fish farming

III.1 Rice production

Use of agricultural chemicals is unavoidable in rice production to control insects and pests but misuse of these will contaminate soil, water and the food chain Survey data

in Table 5 showed that brown plant hopper and blast were the most common threat to rice production in the Cuu Long Delta 84% of farmers in Cantho and 77% in An Giang used insecticides to control brown plant hopper Chemicals for protecting rice against other insects (leaf folder, stemborer, thrips, bugs, etc.) were second in importance and they had been applied only by 16% of farmers in Cantho and 23% of farmers in An Giang province More than 50% of farmers in Cantho and An Giang bought fungicides to control rice blast; other fungal diseases had also been controlled but in less than 50% of cases Survey data showed that 90% of farmers in Cantho applied correct dosages of agricultural chemicals but this figure in An Giang was lower than in Cantho (only 77%) Timing for chemical applications was varied depending on occurrences or observations

on outbreak of pests Farmers in An Giang province had a tendency to spray chemicals based on observation (80%) but farmers in Cantho preferred to use chemicals periodically (52%)

Regarding environmental protection, farmers collected used chemical bottles and sold plastic wastes for recycling (70% of case in An Giang) or buried them However, burning or discarding them were practiced by 60% of cases in Cantho and 16% in An Giang These practices should be avoided to reduce air, soil and water pollution (Table 5)

Technology dissemination and transfer to farmers are very necessary to improve their knowledge for better management of rice and fish farming This routine work is done regularly every year Nearly 70% of farmers in Cantho had been trained in agricultural production but in An Giang province the proportion was below 50% Besides this farmers could also access new technologies through radio or television (Table 6) Rice varieties is one of the decisive factors to increase yield All of farmers in Cantho and An Giang knew ways to get new varieties of rice (through research institution, centre, state farm and/or exchange with other farmers)

The most severe threat to the environment is burning of rice straw in triple rice system even though farmers had been taught many alternative methods to mitigate this effect (straw mushroom cultivation, composting, feeding cattle) Shortage of labour, time, difficulty in transportation, high cost of petrol, unavailability of space for treating rice straw are reasons for non-adoption of sustainable straw management (Table 6)

Table 5 Uses of chemicals in rice production

Insecticides

Fungicides

Blast (Beam, Flash, Fuan, Trizole, Kasai,

Repsai)

60 52

Dosage

Timing

Container treatment

Table 6: Accessibility to information on rice production techniques (%)

Information

Rice varieties

Use of agricultural by products

III.2 Fish production

Catfish has been raised in An Giang province for a long time but culture areas

were limited by numbers of fingerlings that could be harvested naturally (at Chau Doc

district – An Giang province) during flooding time normally at August to October when

they travel down to Cuu Long delta from Tonle Sap catchment of Cambodia Catfish

industry has been developed very quickly only after the year 2000 when Can Tho

University developed techniques to produce fingerlings of catfish artificially and

international market for export was established

Catfish industry is quite new to farmers which is why support by government in

dissemination of technology is really important through broadcasting, printed materials or

even sending technicians to field sites Data in Table 7 showed that this support to fish

raising farmers was considerable An Giang province has the largest catfish industry of

the Cuu Long delta both in area and total production Fish raising farmers in An Giang

paid more attention to information or techniques than those in Can Tho (82% in An

Giang comparison to 75% in Can Tho) They also received support from technicians

more than in Cantho (Table 7) Fish culture requires substantial labour for routine work

such as feeding, pumping water and even guarding at night time as a result numbers hired

labourers in An Giang was much higher than in Can Tho

Table 7: General information on fish culture

Type of fish culture (%)

Average time for fish raising (month)

Depth of fishpond (m)

There was not much difference in time of raising fish or depth of fishpond as well

as density of fish per square metre between the two locations However, density was quite

varied among farmers from the lowest of 12 fish to the highest of 60 fish/m2 There was a

high positive correlation between fishpond size or area and total fish harvesting (r =

+0.842) but negative correlation between area and depth of fishpond (r = -0.365)

Farmers having larger areas can raise high numbers of fish so they can harvest more than

those who have smaller area On the other hand, farmers holding small areas wanted to

increase their production by increasing fish density/m2 This had been proved by negative

correlation between area and fish density (r = -0.520)

Farmers in Cantho preferred to use pellets for raising catfish while those in An

Giang mainly prepared feed by themselves due to availability of discard sea fish from the

adjacent coastal Kien Giang province As a result, conversion factor from feed to meat in

An Giang was higher than in Cantho and this figure was more or less the same in Dong

Thap province which had a conversion of 1.47 (Pham quoc Nguyen 2008) Cantho and

Dong Thap had many feed companies which were close to fishpond sites In preparation

of ball feed, most farmers had to add additives either in the form of concentrated premix

comprising vitamins, enzymes and minerals besides using some traditional inputs like

rice bran, soybean and broken rice Most farmers gave feed two times per day (Table 8)

normally at early morning and before sunset Others fed catfish once or four times per

day but these practices were not common in the Cuu Long delta Regarding the quantity

of feed given per time, all of farmers at two sites said they supplied just sufficient food

for fish about 1/10 of fish weight because surplus feed can ruin water quality The most

common practice by farmer to detect any change in water quality was done by

observation of water colour

Table 8: Feed quality and feeding times/day

Type of feed (%)

Types of additive

Times of feeding/day

Observation

Catfish raising ponds experience high fish mortality Survey data indicated that

losses for raising seed was about 50% and that of commercial fish was a little more than

20% (Table 9) Diseases spreading by polluted water and fish sources were among causes

for high mortality Different diseases on catfish were reported (Table 10) mainly caused

by parasites and virus Farmers blamed fish sources for fish death but the main reason for

this was caused by carrying high numbers of fingerlings in close bag or container During

transportation they were hurt by scratching because catfishes have very sharp spines on

their heads Another reason is caused by changing environment when fishes were put in

to new ponds for raising Those two causes collectively cause high mortality when

re-stocking ponds According to farmers, environment also affected fish heath but this was

not so important in comparison to the other two cases cited above

Interviewed on planning for catfish production in the near future, most farmers in

An Giang province (85%) and Cantho (68%) said they do not have any intention to invest

more on catfish production This revealed that farmers were not so happy with catfish

production because there are a lot of uncertainties in price of selling fish, inputs (feeding,

chemicals for water treatment and diseases controls) Under market oriented economics

system, low level educated farmers should be assisted in production in order to increase

their profits Only 25% of farmers in Cantho and 11% of those in An Giang planned to

increase their production Again this data confirms that catfish production could not

attract more farmers to invest on this job Planning for set up settling ponds was also not

being considered by most of the farmers interviewed Quite a few farmers were reluctant

to answer during interview but really they have never think about it

Table 9: Percentage of mortality and causes

Mortality rate

Causes of loss

Current fish status

Planning for future production

Concerning on the use of bio-products and chemicals for water treatment in

catfish culture, nearly 50% of farmers at both sites had used Vikong, BKC, Bioca, Yulai,

Aquapure, Prawbac and some other products (Table 10) They also used antibiotics to

control mainly bacterial diseases in the digestive tract of catfish Some common

antibiotics like Amoxycilline, Cotrim, Penicilline, Kanamycine, Oxamet and Tetracylline

had been used mainly by mixing into feeds in An Giang (96%) or putting directly into

water (40% of farmers in Cantho following this method) According to farmers, these

antibiotics were very effective to control catfish diseases Fortunately, almost all of

farmer used antibiotics at recommended dosage otherwise these chemicals will cause

problems to the environment and possibly in international markets also For sanitary

purposes and control of algae in fishpond, 93% of farmers in Cantho and about 66% in

An Giang province applied copper sulphate, BKC, Vikong, Chlorine, juka and even salt

or lime (Table 10) Among these BKC and chlorine were the most common chemicals

which had been used both in An Giang and Cantho

Water management is very important in catfish culture for new and current used

ponds All farmers normally spreaded lime or salt along the sides and bottom of pond

after making a new one or after draining out all water after harvesting fish from ponds

Dosages of lime and salt varied from 300-400 kg/ ha Pond will then be kept dried from

3-5 days before pumping water in for a new crop More than 95% of farmers changed

and/or added water to fish ponds regularly (about 1/3 volume of pond) and there was

about 50% farmers at both sites who practiced bottom of fishpond cleaning by pumping

out sludge while raising catfish to secure good water quality However, all of farmers had

to pump sludge out of their pond after harvesting fish (Table 11) The practice of

discharging waste directly to water source could caused water pollution Most of farmers

had handheld a pH meter to monitor water quality Other ways to detect water quality

were by observation of water colour or smelling the odour of water If oxygen is deficient

most of fishes will come to surface of water early morning; farmers will then know

oxygen in fishpond is sufficient or not

Table 10: Chemicals used for water treatment

Table 11: Water management in catfish culture

Filled up and/or changed water periodically (%) 98 100

Water quality monitoring

Sludge discharged

Survey data on diseases of catfish are presented in Table 12 The most severe and

widespread disease to catfish is caused by bacteria (about 90%) causing death of catfish

The most common symptoms of bacterial disease called haemorrhage producing red

appearance on mouth, fins and tail Other diseases are called swelling head and slimy loss

but they are of minor importance